Mixing device

ABSTRACT

A mixer without moving parts for intimately combining different materials such as resins, foods, paints, cosmetics, bulk chemicals, pharmaceuticals, dry powders, and the like, including an elongate tubular structure having an inlet adapted to receive a stream of two or more relatively unmixed materials, an outlet, and a plurality of sections between the inlet and outlet shaped to thin and widen the stream flowing longitudinally from inlet to outlet and fold the thinned stream laterally over upon itself, then repeat the thinning and folding process as many times as desired or necessary to produce intimate mixing.

Unite Sttes atent [72] Inventor George H. White Mundelein, Ill. [21] Appl. No. 71,867 [22] Filed Sept. 14,1970 [45] Patented Jan. 4, 1972 [73] Assignee Moday, Inc.

[54] MIXING DEVICE 8 Claims, 4 Drawing Figs.

[52] US. Cl t. 259/4, 138/38, 165/177 [51] Int. Cl B011 5/00, FlSd 1/14 [50] Field of Search 259/4, 18, 36; 138/38; 165/177, 179

[56] References Cited UNlTED STATES PATENTS 3,206,170 v 9/ 1965 W Schippers et a1 259/4 3,239,197 3/1966 Tollar 259/4 3,358,749 12/1967 259/4 X 3,394,924 7/1968 259/4 3,460,809 8/1969 259/4 Primary Examiner-Walter A. Scheel Assistant Examiner-Philip R. Coe Att0meyI-lofgren, Wegner, Allen, Stellman and McCord ABSTRACT: A mixer without moving parts for intimately combining different materials such as resins, foods, paints, cosmetics, bulk chemicals, pharmaceuticals, dry powders, and the like, including an elongate tubular structure having an inlet adapted to receive a stream of two or more relatively unmixed materials, an outlet, and a plurality of sections between the inlet and outlet shaped to thin and widen the stream flowing longitudinally from inlet to outlet and fold the thinned stream laterally over upon itself, then repeat the thinning and folding process as many times as desired or necessary to produce intimate mixing.

PATENTED JAN 4 I572 MIXING DEVICE BACKGROUND'OF THE INVENTION In particular, this invention relates to a mixing device for combining resins, such as epoxies and polyesters, for use as bonding agents in lamination processes.

In the past, in this art there have been problems in metering resin components, adequately mixing the components, and dispensing the mixture for proper use at the desired time and place. The problem of adequate mixing has been foremost. The problem of timing is significant particularly where the reaction time is short.

One approach to metering, mixing and dispensing has involved premixing in large batches as by mechanical agitators. While this permits some degree of effectiveness in mixing and uniformity in various samples of a given batch, it contemplates mixing at a time and place remote from actual use. As a result, there is a necessity for adequately packaging, storing and transporting the mixed product, and these often involve freezing the mixture and maintaining such state until use. Needless to say, it is expensive to freeze the material and maintain it frozen during shipping and storage. Further, mechanical agitation often entraps air and vaporizes some ingredients, thereby creating gaseous bubbles. The bubbles alter the adhesive and cohesive qualities, as well as other characteristics, as a result of which degaming is often necessary.

Another approach has involved use of mixing spray guns. However, many resins react and begin to cure immediately upon mixing, and the guns do not scour out all corners and crevasses continuously while in use, as a result of which the guns must be taken out of use, torn down, and cleaned meticulously every few hours. The cleaning may be necessary even though the gun was in use only for a few minutes. Some guns include purging systems, but these are not effective if the materials will not react with a solvent, which is often the case with epoxies. If timely cleaning is not effected, the problem is extremely difiicult after curing.

Still another approach has involved socalled static mixers. These have in most part relied upon a process of dividing and rejoining, or a process of diverting or deviating flow. Some such devices appear to be somewhat ineffective, and to the extent they are efi'ective, it appears to be due to turbulence which is not easily predictable.

SUMMARY OF THE INVENTION The present invention seeks to obviate the problems of the past and to provide a static mixing device which is simple, inexpensive, selfcleaning and efficient.

In a preferred form, it includes an elongate tubular structure having means defining a passage to thin and widen a longitudinally flowing stream, and fold the thinned and widened stream over upon itself.

It is an object of the invention to provide a new and improved static mixing device of the character described, with means to thin, widen and fold a longitudinal stream laterally over upon itself.

A more specific object is to provide a new and improved mixing device without moving parts, including a plurality of tubular members end to end, each having a generally rectangular inlet passage area, an intermediate passage area of decreasing thickness and increasing width, and an outlet passage area having a minimum thickness and a maximum width and folded laterally upon itself, together with means connecting the tubular members with the outlets of preceding members at the inlets of succeeding members to join the folded layers of the stream and repeat the thinning, widening, folding and joining thereby to intimately mix in increasing layers of decreasing thickness.

The improved device of the present invention may be disposable or permanent. It may be opaque or transparent to permit visual inspection. It may be metal or glass or plastic. While particularly suited for mixing resins, it may be used with other fluids and with solids. There are no crevasses, corners or pockets which are not scoured continuously by flow of material, as a result of which cleaning is simplified. There is no contact of different ingredients until mixing begins, which is important where reaction time is short. There is no waste in stopping and starting. The closed system prohibits contamination by exposure to air or other gases or foreign matter, and prevents entrapment of air.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a plan view of a mixing device embodying the principles of the present invention;

FIG. 2 is an enlarged exploded perspective view showing the formation of a mixing element and its joint with another;

FIG. 3 is a perspective view of a blank from which the mixing element is made; and

FIG. 4 is a top view of the blank of FIG. 3 in flattened form, preparatory to shaping shown in FIG. 2.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT As illustrated herein, a mixing device embodying the principles of the present invention is generally designated by the reference number 10, and comprises an elongate tubular structure having a passage therethrough from an inlet 12 to an outlet 14. The inlet 12 is formed in an inlet member 16 and the outlet in an outlet member 18. Between the inlet member 16 and the outlet member 18, there are a plurality of tubular mixing members, eight as illustrated, of similar configuration though varied disposition, designated 20-1 through 20-8, disposed end to end and in line with the inlet and outlet members. The members 16, 18 and 20 are joined end to end to provide a continuous passage from the inlet 12 to the outlet 14. As illustrated, the outlet end of each preceding member is telescoped in the inlet end of each succeeding member and suitably bonded thereto as by welding or brazing in a construction involving metallic materials. However, the materials may be other than metal and the joints may be other than telescopic. In particular, butt joints may be used.

The inlet member 16 is formed with a cylindrical inlet portion 160 and a flattened widening outlet portion 16b. The inlet portion 16a is adapted for connection with any suitable supply of cylindrical configuration, such as a tubular section (not shown) with Y- shaped branches or other plural inlets so that a plurality of different materials may be introduced in relatively unmixed fashion and then intimately mixed as the stream flows longitudinally through the mixing device. The outlet portion 16b terminates in a flattened, widened end having a passage area of generally oval or rectangular configuration and adapted to fit in the inlet end of the succeeding member 20-1.

The mixing members 20 are formed with an inlet portion 20a having a passage area of generally oval or rectangular configuration, an intermediate portion 20b of increasing width and decreasing thickness, and an outlet portion 20c having a passage area with a thickness about half the thickness of inlet portion 200 and a width about twice the width of the inlet portion 200. In the intermediate portion 20b and the outlet portion 200, the member is folded laterally (relative to the longitudinal axis) over upon itself, so that as the ingredients flow longitudinally in each mixing section, it is thinned, widened and folded over. Upon leaving each outlet portion 200 and entering the succeeding inlet portion 20a, the folded layers are joined together in overlying relationship, and the thinning, widening, folding and joining is repeated, to provide intimate mixing in increasing layers of decreasing thickness.

As illustrated, the successive mixing chambers 20 are angularly disposed clockwise (looking from inlet toward outlet) about the longitudinal axis from the preceding member, so that in the member 20-1 the trough formed by the fold faces up from the plane of the paper, the member 20- 2 faces down in the plane of the paper, the member 20-3 faces down into the plane of the paper, the member 20-4 faces up in the plane of the paper, and so on. However, such progression is not critical and the angular arrangement may be random.

The mixing members are formed from blank parts as illustrated in FIGS. 3 and 4. In FIG. 3 it will be seen that inlet portion 200 is of relatively small cylindrical shape, intermediate portion 20b is of conical shape, and outlet portion 20c is of relatively large cylindrical shape. In FIG. 4, the rounded blank of FIG. 3 has been flattened preparatory to the bending step which produces the shape of FIG. 2.

At the outlet end of each mixing chamber 20, between the inner layers of the folded material of the mixing member as at 20d, there is a narrow space, however slight it may be, which is appropriately sealed in order to provide a fluidtight passage through the mixing device. As illustrated in FIG. 2, the space 20d is filled with material 22, which may be solder, for example, if appropriate metal is used in the mixing members.

The outlet member 18 is much like the inlet member 16 in inverse order, including a flattened inlet portign 18a and a cylindrical outlet portion 18b.

In operation, the function of the mixing device will be understood to permit introduction of relatively unmixed materials in inlet member 16, repeated thinning, widening, folding and joining in members 20 and 18, to deliver an intimate mixture to outlet 14 in the form of many layers of minute thickness. The number of mixing members 20 may be varied to suit the materials involved and the degree of mixing required. While the preferred embodiment shown has been developed for mixing epoxy resins, similar principles may be employed in mixing other materials. The crosssectional area of the passage through the mixing device is generally uniform throughout the length so that no substantial back pressure is created, though there may be minor variations due to particular forming processes. While the device has been described in a manner utilizing the end 200 of each mixing element as the inlet, and such use is understood to be most efiective, mixing may be obtained by utilizing the end 200 of each mixing element as the inlet. In one contemplated use, the mixing device may be positioned in a tube between two opposite end portions filled with separate materials adapted to be mixed by movement back and forth through the mixer.

I claim:

1. A mixing device, comprising, an elongate tubular structure having an inlet adjacent one end, an outlet spaced from the inlet, and means defining a passage communicating the inlet with the outlet and shaped to thin and widen a stream flowing longitudinally from the inlet toward the outlet, and fold the thinned and widened stream laterally upon itself, and join the folded iayers of the stream.

2. A mixing device as defined in claim 1, wherein the means forming said passage comprises a tubular member having an inlet end of generally oval cross section, an intermediate portion of decreasing thickness and increasing width, and an outlet end having a minimum thickness and a maximum width and folded laterally over upon itself.

3. A mixing device as defined in claim I wherein the means forming said passage comprises a tubular member defining an inlet passage area of generally rectangular cross section, an intermediate passage area of decreasing thickness and increasing width, and an outlet passage area having a thickness about half the inlet thickness and a width about twice the inlet width, and folded laterally over upon itself.

4. A static mixing device for combining longitudinally flowing materials, comprising, an elongate tubular structure having an inlet at one end for receiving a stream including a plurality of relatively unmixed materials, an outlet at the opposite end for discharging intimately mixed materials, and means defining a passage connecting the inlet and the outlet and shaped to thin, widen and fold the longitudinally flowing stream over upon itself, join the folded layers of the stream, and then repeatedly thin, widen, fold and join to provide intimate mixing of the materials in increasing layers of decreasing thickness.

5. A static mixing device as defined in claim 4, wherein the means defining said passage comprises a plurality of tubular members end to end each having an inlet end defining a passage area of generally rectangular cross section, an intermediate portion defining a passage area of decreasing thickness and increasing width, and an outlet end defining a passage area having a minimum thickness and a maximum width and folded laterally over upon itself, and means joining the tubular members with the inlets of succeeding members at the outlets of preceding members.

6. A static mixing device as defined in claim 5 wherein each tubular member has an outlet passage area approximately equal the inlet passage area with a thickness about half the inlet thickness and a width about twice the inlet width.

7. A static mixing device as defined in claim 5 wherein the outlet ends of preceding tubular members are telescoped within the inlet ends of succeeding tubular members.

8. A mixing device, comprising, an elongate tubular structure having an inlet adjacent one end, an outlet spaced from the inlet, and means defining a passage communicating the inlet with the outlet, including a tubular member having one end of generally oval cross section having a maximum thickness and a minimum width, an intermediate portion of decreasing thickness and increasing width, and an opposite end having a minimum thickness and a maximum width and folded laterally over upon itself. 

1. A mixing device, comprising, an elongate tubular structure having an inlet adjacent one end, an outlet spaced from the inlet, and means defining a passage communicating the inlet with the outlet and shaped to thin and widen a stream flowing longitudinally from the inlet toward the outlet, and fold the thinned and widened stream laterally upon itself, and Join the folded layers of the stream.
 2. A mixing device as defined in claim 1, wherein the means forming said passage comprises a tubular member having an inlet end of generally oval cross section, an intermediate portion of decreasing thickness and increasing width, and an outlet end having a minimum thickness and a maximum width and folded laterally over upon itself.
 3. A mixing device as defined in claim 1 wherein the means forming said passage comprises a tubular member defining an inlet passage area of generally rectangular cross section, an intermediate passage area of decreasing thickness and increasing width, and an outlet passage area having a thickness about half the inlet thickness and a width about twice the inlet width, and folded laterally over upon itself.
 4. A static mixing device for combining longitudinally flowing materials, comprising, an elongate tubular structure having an inlet at one end for receiving a stream including a plurality of relatively unmixed materials, an outlet at the opposite end for discharging intimately mixed materials, and means defining a passage connecting the inlet and the outlet and shaped to thin, widen and fold the longitudinally flowing stream over upon itself, join the folded layers of the stream, and then repeatedly thin, widen, fold and join to provide intimate mixing of the materials in increasing layers of decreasing thickness.
 5. A static mixing device as defined in claim 4, wherein the means defining said passage comprises a plurality of tubular members end to end each having an inlet end defining a passage area of generally rectangular cross section, an intermediate portion defining a passage area of decreasing thickness and increasing width, and an outlet end defining a passage area having a minimum thickness and a maximum width and folded laterally over upon itself, and means joining the tubular members with the inlets of succeeding members at the outlets of preceding members.
 6. A static mixing device as defined in claim 5 wherein each tubular member has an outlet passage area approximately equal the inlet passage area with a thickness about half the inlet thickness and a width about twice the inlet width.
 7. A static mixing device as defined in claim 5 wherein the outlet ends of preceding tubular members are telescoped within the inlet ends of succeeding tubular members.
 8. A mixing device, comprising, an elongate tubular structure having an inlet adjacent one end, an outlet spaced from the inlet, and means defining a passage communicating the inlet with the outlet, including a tubular member having one end of generally oval cross section having a maximum thickness and a minimum width, an intermediate portion of decreasing thickness and increasing width, and an opposite end having a minimum thickness and a maximum width and folded laterally over upon itself. 